iio_rwdev

iio_rwdev - read/write buffers from/to an IIO device

SYNOPSIS

iio_rwdev [ options ] [-n <hostname>] [-t <trigger>] [-T <timeout-ms>] [-b <buffer-size>] [-i <buffer-index>] [-s <samples>] [-w] [-c] <iio_device> [<channel> …]

DESCRIPTION

iio_rwdev is a utility for reading buffers from connected IIO devices, and sending results to standard out.

OPTIONS

-h, –help

Tells iio_rwdev to display some help, and then quit.

-V, –version

Prints the version information for this particular copy of iio_rwdev and the version of the libiio library it is using. This is useful for knowing if the version of the library and iio_rwdev on your system are up to date. This is also useful when reporting bugs.

-S, –scan [backends]

Scan for available IIO contexts, optional arg of specific backend(s) ‘ip’, ‘usb’ or ‘ip,usb’. Specific options for USB include Vendor ID, Product ID to limit scanning to specific devices ‘usb=0456:b673’. vid,pid are hexadecimal numbers (no prefix needed), “*” (match any for pid only) If no argument is given, it checks all that are available.

-w –write

Write sample data to the IIO device. The default is to read samples from it.

-t –trigger <arg>

Use the specified trigger, if needed on the specified channel

-r –trigger-rate <arg>

Set the trigger to the specified rate (Hz). Default is 100 Hz.

-b –buffer-size <arg>

Size of the capture buffer. Default is 256.

-i –buffer-index <arg>

Buffer index to use. Default is 0. On multi-buffer devices, different buffers may have different sets of scan elements and directions.

-s –samples <arg>

Number of samples (not bytes) to capture, 0 = infinite. Default is 0.

-c –cyclic

Use cyclic buffer mode.

-B –benchmark

Benchmark throughput. Statistics will be printed on the standard input.

-u, –uri

The Uniform Resource Identifier (uri) for connecting to devices, can be one of:

ip:[address]

network address, either numeric (192.168.0.1) or network hostname

ip:

blank, if compiled with zeroconf support, will find an IIO device on network

usb:[device:port:instance]

normally returned from iio_rwdev -S

serial:[port],[baud],[settings]

which are controlled, and need to match the iiod (or tinyiiod) on the other end of the serial port.

[port]

is something like ‘/dev/ttyUSB0’ on Linux, and ‘COM4’ on Windows.

[baud]

is normally one of 110, 300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 38400, 57600, 115200 [default], 128000 or 256000, but can vary system to system.

[settings]

would normally be configured as ‘8n1’ this is controlled by:

data_bits:: (5, 6, 7, 8 [default], or 9)
parity_bits:: (‘n’ none [default], ‘o’ odd, ‘e’ even, ‘m’ mark, or ‘s’ space)
stop_bits:: (1 [default, or 2)
flow_control:: (‘0’ none [default], ‘x’ Xon Xoff, ‘r’ RTSCTS, or ‘d’ DTRDSR)

local:

with no address part.

-T, –timeout <arg>

Context timeout in milliseconds. 0 = use backend default, -1 = wait forever, ‘nb’ or ‘nonblocking’ = non-blocking mode. Default is 0.

RETURN VALUE

If the specified device is not found, a non-zero exit code is returned.

USAGE

You use iio_rwdev in the same way you use many of the other libiio utilities. You should specify a IIO device, and the specific channel to read or write. When reading, channels must be input; when writing they must be output. If no channel is provided, iio_rwdev will read from all input channels or write to all output channels. If no device is provided, iio_rwdev will print a few examples:

``iio_rwdev`` -a

Using auto-detected IIO context at URI “usb:3.10.5”

Example : iio_rwdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage0

Example : iio_rwdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage1

Example : iio_rwdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage2

Example : iio_rwdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc voltage3

Example : iio_rwdev -u usb:3.10.5 -b 256 -s 1024 cf-ad9361-lpc

This captures 1024 samples of I and Q data from the USB attached AD9361, and stores it (as raw binary) into the file samples.dat

``iio_rwdev`` -a -s 1024 cf-ad9361-lpc voltage0 voltage1 > samples.dat

And plots the data with gnuplot.

``gnuplot`` -e “set term png; set output ‘sample.png’; plot ‘sample.dat’ binary format=’%short%short’ using 1 with lines, ‘sample.dat’ binary format=’%short%short’ using 2 with lines;”

BUGS

All bugs are tracked at: https://github.com/analogdevicesinc/libiio/issues